1. Field of the Invention
The present invention relates to a heat exchanger, particularly to a heat exchanger having a novel design of fins and tubes.
2. Description of Related Art
A conventional plate type heat exchanger comprises a plurality of fins linked with tubes. The tubes are connected to a fluid pumping unit, e.g., a attach block, a compressor or a pump. In case of the attach block being associated with a heat source, fluid inside the tubes absorb heat generated by the heat source via the attach block and the heat can be dissipated by the fins. After this, the fluid again receives heat to perform another cycle of heat exchange repeatedly. Conventional fins are made with equipment entirely different from that for making the tubes so that it results in high expenses for the equipments and molding tools. Assembling various shapes and sizes of fins with the tubes is not readily done and working hours for the assembly job are higher so that manufacturing cost increase relatively. Conventionally, fins and tubes are joined by way of pressing or brazing. But, the pressed joints may result in high thermal resistance with low efficiency of heat transfer and the brazed joints may become crystallized to result in lower efficiency of heat transfer. Furthermore, the conventional plate type heat exchanger provides a fan to blow fresh air towards the fins and the tubes for accelerating heat dissipation. Ordinarily, air flow outside the tubes and fluid flow inside the tubes run across each other forming cross flows so that it occurs a phenomenon of temperature gradient between hot fluid at cross section of the inlet and the cool fluid at cross section of the outlet in the heat exchanger. Therefore, the tube has to be coiled multiply to ensure uniform temperature distributions. This, however, causes increased pressure loss within the system and thus reduced the efficiency of heat exchange, while the phenomenon of temperature gradient is still not completely eliminated. Therefore, when the heat exchanger is used in conjunction with an air conditioning system, the refrigerant flowing inside the tubes and air blown outside lead to the cool air out of the discharge port thereof with a non-uniform temperature distribution and it will result in a problem of unsatisfactory temperature sensitivity.
It is the main object of the present invention to provide a heat exchanger with integrated fins and tubes, which can eliminate thermal contact resistance occurring at the conventional joining points of the fins and tubes and enhance the efficiency of thermal conductivity.
Another object of the present invention is to provide a heat exchanger having integrated fins and tubes, with which working hours and equipment expense are reduced and it is possible to adapt to size changes of products for lowering the manufacturing cost.
A further object of the present invention is to provide a heat exchanger in which internal fluid and external air are arranged to counter flow to each other so that the efficiency of heat exchange can be enhanced and the phenomenon of temperature gradient can be eliminated to enhance the sensitivity of comfortable temperature.